The present invention relates to computer systems, in particular to computer systems suitable for multiprocessor systems, for example multiprocessor server systems.
One application for the present invention relates to high density computer systems, for example, computer server systems for telecommunications applications. In telecommunications applications, it is important to provide high reliability and high capacity of operation. Various approaches have been taken to providing such high-performance, high reliability systems. Typically such systems are designed around providing redundant resources so that if one component of the system develops a fault, the system remains operational using the redundant resources. Fault tolerance can also be achieved, for example, with multiprocessor systems that provide redundancy through dynamic, e.g., software-controlled, task distribution. High density systems are typically rack mountable, with one or more processor systems occupying a shelf in the rack. The trend in recent times is to make the computers with smaller form factors. This means that more computers can be located in a rack. This has the advantage of increasing the processing density within the racks, and also the advantage of reducing the distance between the computer systems.
One factor in computer system reliability is that failure of one component in a computer system may require the entire computer system to be taken offline for repairs to be effected. This therefore reduces the up-time of the computer to below acceptable levels for many applications. Such component failure is especially troublesome where the component is a component which is not replaceable by an unskilled worker. Such components are therefore required to have a reliability even higher than the required reliability of components which may be replaced by an unskilled worker.